Anti-parallel tab sensor fabrication

ABSTRACT

A method for fabricating a sensor having anti-parallel tab regions. The method includes forming a free layer having tab areas on opposite sides of an active area, forming a first layer of a carbon composition above the active area of the free layer, the first layer of carbon being substantially absent from tab areas of the free area, forming spacer layers above the tab areas of the free layer, the spacer layers being operable to make magnetic moments of ferromagnetic layers on opposite sides thereof antiparallel, forming bias layers above the spacer layers, the bias layers being operative to substantially pin magnetic moments of the tab areas of the free layer, forming second layers of carbon composition above the tab areas of the free layer, and removing the layers of carbon composition and any portions of the layers overlying the layers of carbon composition.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/439,464, filed on May 16, 2003 now U.S. Pat. 6,954,344.

FIELD OF THE INVENTION

The present invention relates to magnetic heads, and more particularly,this invention relates to lead overlay read heads having magneticallypinned passive regions and methods for fabricating the same.

BACKGROUND OF THE INVENTION

One well known way to increase the performance of hard disk drives is toincrease the areal data storage density of the magnetic hard disk. Thiscan be accomplished by reducing the written data track width, such thatmore tracks per inch can be written on the disk. To read data from adisk with a reduced track width, it is also necessary to developsufficiently narrow read head components, such that unwanted magneticfield interference from adjacent data tracks is substantiallyeliminated.

The standard prior art read head elements include a plurality of thinfilm layers that are deposited and fabricated to produce a GMR readhead, as is known to those skilled in the art. Significantly, where thewidth of the thin film layers that comprise the GMR read head is reducedbelow certain values, the magnetic properties of the layers aresubstantially compromised. To overcome this problem, GMR read heads havebeen developed in which the thin film layers have an ample width and theelectrical leads are overlaid on top of portions of the thin filmlayers. This lead overlaid configuration has the effect of creating anactive read head region having a width that is less than the entirewidth of the deposited layers, such that the magnetic properties of thethin film layers can be preserved. Thus, in the lead overlaid GMR readheads of the prior art, active magnetic layer portions exist between theelectrical leads and passive magnetic layer portions exist beneath theelectrical leads.

A problem that has been recognized with regard to such prior art leadoverlaid read heads is that the passive region of the magnetic layers ofthe read head, and particularly the free magnetic layer, is not entirelypassive. That is, external magnetic fields, such as from adjacent datatracks, create magnetic field fluctuation and noise within the passiveregions of the free magnetic layer beneath the electrical leads. Thus,noise and side reading effects continue to be a problem with leadoverlaid GMR read heads.

FIG. 1 is a side cross-sectional view of a prior art electrical leadoverlaid read head portion of a magnetic head 100. As depicted therein,the prior art lead overlaid read head generally includes a substratebase 102 that constitutes the material from which the magnetic head isfabricated, such as aluminum titanium carbide. A first magnetic shield104 is fabricated on the substrate, and an insulation layer 106,typically composed of aluminum oxide, is fabricated upon the magneticshield 104. A seed layer 108 is deposited upon the insulation layer 106and a series of thin film layers are sequentially deposited upon theseed layer 108 to form a GMR read head. In this structure, the layersgenerally include an antiferromagnetic layer 114, a pinned magneticlayer 118 that is deposited upon the anti ferromagnetic layer 114, aspacer layer 122 that is deposited upon the pinned magnetic layer 118, afree magnetic layer 126 that is deposited upon the spacer layer 122 anda cap layer 130 that is deposited upon the free magnetic layer 126.Typically, the antiferromagnetic layer 114 may be composed of PtMn, thepinned magnetic layer 118 may be composed of CoFe, the spacer layer 122may be composed of Cu, the free magnetic layer 126 may be composed ofCoFe and the cap layer 130 may be composed of Ta.

Following the deposition of the GMR read head layers 114-130, apatterned etching process is conducted such that only central regions140 of the layers 114-130 remain. Thereafter, hard bias elements 148 aredeposited on each side of the central regions 140. Following thedeposition of the hard bias elements 148, electrical lead elements 154are fabricated on top of the hard bias elements 148. As depicted in FIG.1, inner ends 156 of the leads 154 are overlaid on top of outer portions160 of the layers 114-130 of the central read head layer regions 140. Asecond insulation layer 164 is fabricated on top of the electrical leads154 and cap layer 130, followed by the fabrication of a second magneticshield (not shown) and further components that are well known to thoseskilled in the art for fabricating a complete magnetic head.

A significant feature of the prior art lead overlaid GMR read headdepicted in FIG. 1 is that the portion of the central layer region 140which substantially defines the track reading width W of the read head100 is the central portion 144 of the read head layer regions 140 thatis disposed between the inner ends 156 of the electrical leads 154. Thatis, because the electrical current flows through the read head layersbetween the electrical leads 154, the active portion 144 of the readhead layers comprises the width w between the inner ends 156 of theelectrical leads 154. The outer portions 160 of the read head layersdisposed beneath the overlaid inner ends 156 of the electrical leads 154are somewhat passive in that electrical current between the electricalleads 154 does not pass through them.

A significant problem with the prior art lead overlaid read head 100depicted in FIG. 1 is that the magnetization in the outer portions 160of the free layer 126 beneath the electrical leads 154 is unstable andsubject to unwanted magnetic field fluctuations. Additionally, sidereading effects from adjacent data tracks as well as magnetic noise iscreated in the passive portions 160 of the free layer 126 beneath theelectrical lead ends 156. Thus, noise and side reading effects continueto be a problem with lead overlaid GMR read heads.

Further, prior art heads have hard bias material on either side of thesensor to exert magnetic force on the free layer to magneticallystabilize the free layer. The problem is that hard bias layers are verythick, and as track sizes shrink, sensors must get smaller. When thetrack width becomes very narrow, the hard bias layers makes the freelayer very insensitive and thus less effective. What was needed was away to create a sensor with a narrow track width, yet with a free layerthat is very sensitive.

To overcome the problems described above, some heads are now constructedsuch that the magnetization of the free magnetic layer is pinned in thepassive regions beneath the overlaid electrical leads, thus stabilizingthe passive regions, and reducing noise and side reading effects.

FIG. 2 depicts another prior art lead overlaid read head 200. Asdepicted therein, the read head 200 includes a GMR read head thin filmelement 240, as well as the hard bias elements 248. As depicted therein,the prior art lead overlaid read head generally includes a substratebase 202 that constitutes the material from which the magnetic head isfabricated, such as aluminum titanium carbide. A first magnetic shield204 is fabricated on the substrate, and an insulation layer 206,typically composed of aluminum oxide, is fabricated upon the magneticshield 204. A seed layer 208 is deposited upon the insulation layer 206and a series of thin film layers are sequentially deposited upon theseed layer 208 to form a GMR read head. In this structure, the layersgenerally include an antiferromagnetic layer 214, a pinned magneticlayer 218 that is deposited upon the anti ferromagnetic layer 214, aspacer layer 222 that is deposited upon the pinned magnetic layer 218, afree magnetic layer 226 that is deposited upon the spacer layer 222 anda cap layer 230 that is deposited upon the free magnetic layer 226.

This read head 200 includes an additional magnetic thin film layer 270that is deposited on top of the hard bias elements 248, such that aninner portion 210 of the layer 270 extends over the outer portions 260of the layers that comprise the read head element 240. The magneticlayer 270 is deposited on top of the outer portions 260 of the tantalumcap layer 230, and directly on top of the magnetic hard bias elements248. The electrical leads 254 are thereafter fabricated on top of themagnetic layer 270.

Following the magnetic field initialization of the hard bias elements248, the magnetic field of the hard bias elements 248 will createcorresponding magnetic fields within the magnetic layer 270.Furthermore, because the inner portion 210 of the magnetic layer 270 isdeposited on top of the outer portion 260 of the tantalum cap layer 230,which is deposited above the outer portion 260 of the free layer 226,the magnetic field within the inner portion 210 of the magnetic layer270 will become magnetostatically coupled to the outer portion 260 ofthe free layer 226 through the tantalum cap layer 230. This provides apinning effect upon the magnetic fields within the outer portion 260 ofthe free layer, because it raises the coercivity of the free layerwithin the outer region 260.

One problem encountered during manufacture of a lead overlaid read headis that when plating this kind of sensor, layer 226 is deposited, thenlayer 230 is deposited, then layer 270 is deposited as a contiguouslayer. Then the portion of magnetic layer 270 in the central portion 244of the read head layer regions 240 must be etched off without breakingthrough the cap layer 230. Some prior art processes use the cap layer230 as a marker indicating when to stop etching. However, this layer 230is typically only ˜8 angstroms or less, so there is danger of etchingthrough the layer 230 and into the free layer 226.

Another drawback is that the prior art read heads 100,200 of FIGS. 1-2require hard bias elements 148, 248. As track sizes shrink, sensors mustget smaller. The smaller the sensor becomes, the more susceptible it isto interference from the hard bias elements 148, 248. When the trackwidth becomes very narrow, the hard bias elements 148, 248 make the freelayer very insensitive and thus less effective.

Another prior art method of creating heads with the magnetic moment ofthe free layer pinned in the outer regions is to oxidize the section ofthe magnetic layer in the active area. This makes the materialnonmagnetic and thus inactive. FIG. 3 illustrates a lead overlaid readhead 300 according to one preferred embodiment. As shown, the read head300 includes a substrate base 302, a first magnetic shield 304fabricated on the substrate, and an insulation layer 306 fabricated uponthe magnetic shield 304. A seed layer 308 is deposited upon theinsulation layer 306 and a series of thin film layers are sequentiallydeposited upon the seed layer 308 to form a GMR read head. In thepreferred embodiment of the present invention, the layers generallyinclude an antiferromagnetic layer 310, a lower pinned layer 312, afirst spacer layer 314, a free magnetic layer 318 that is deposited uponthe first spacer layer 314, a second spacer layer 322 that is depositedupon the free layer 318, a bias magnetic layer 326 that is depositedupon the second spacer layer 322 and a cap layer 330 that is depositedupon the bias layer 326. The magnetic moments of the free and biaslayers are antiparallel.

The section of the magnetic layer is oxidized in the active area 344.The problem encountered here is that the second spacer layer 322separating the free layer 318 and the bias magnetic layer 326 istypically 8 angstroms or less, so some of the oxidizing material canmigrate through the second spacer layer 322, reaching the free layer 318and oxidizing it. The oxidation in turn affects the signal qualityachievable from the free layer 318.

In addition, because the second spacer layer 322 is crystalline, duringthermal cycling of the head, and because of the heat generated duringuse, oxygen can diffuse through the second spacer layer 322 and oxidizethe free layer 318, reducing its effectiveness.

What is needed is a way to form a sensor structure having antiparalleltab regions without excessive and dangerous processing on the activeregion of the sensor.

SUMMARY OF THE INVENTION

The present invention overcomes the drawbacks and limitations describedabove by providing a method of fabrication for an anti-parallel tabsensor. In this method, the active area of the sensor is protected anduntouched during the fabrication. This assures improvedperformance/sensor stability over the alternative method where biaslayer in the active area is oxidized to kill its magnetization.

In one embodiment, a free layer is formed and capped. A first layer of acarbon composition is formed above the active area of the free layer. By“above”, what is meant is that a particular portion of a layer ispositioned approximately above the referenced portion of the layer belowwhen the structure is positioned in the orientation shown in thedrawings attached hereto. A layer of resist is formed above the firstlayer of carbon composition. The resist and preferably any carboncomposition are removed from above the tab areas, preferably usingphotolithography and etching. The cap above the tab areas is removed,preferably using reactive ion etching and sputtering. Spacer layers areformed above the tab areas of the free layer, the spacer layers beingoperable to make magnetic moments of ferromagnetic layers on oppositesides thereof antiparallel. Bias layers are formed above the spacerlayers, the bias layers being operative to substantially pin magneticmoments of the tab areas of the free layer. Leads are formed above thebias layers. Second layers of carbon composition are formed above thetab areas of the free layer. The layers above a plane extending parallelto portions of the second layer of carbon composition above the tabareas are removed using chemical-mechanical polishing. Finally, anyremaining carbon composition is removed, preferably using reactive ionetching.

Another method for fabricating a sensor having anti-parallel tab regionsincludes forming a free layer having tab areas on opposite sides of anactive area, forming a first layer of a carbon composition above theactive area of the free layer, the first layer of carbon beingsubstantially absent from tab areas of the free area, forming spacerlayers above the tab areas of the free layer, the spacer layers beingoperable to make magnetic moments of ferromagnetic layers on oppositesides thereof antiparallel, forming bias layers above the spacer layers,the bias layers being operative to substantially pin magnetic moments ofthe tab areas of the free layer, forming second layers of carboncomposition above the tab areas of the free layer, and removing thelayers of carbon composition and any portions of the layers overlyingthe layers of carbon composition.

A sensor manufactured according to the process above includes a freelayer having tab areas on opposite sides of an active area, spacerlayers formed only on the tab areas of the free layer, the spacer layersbeing operable to make magnetic moments of ferromagnetic layers onopposite sides thereof antiparallel, bias layers above the spacerlayers, the bias layers being operative to substantially pin magneticmoments of the tab areas of the free layer, and leads formed above thebias layers. The sensor may form part of a GMR head, a CPP GMR sensor,or a tunnel valve sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings.

FIG. 1 is a side cross-sectional view of a prior art lead overlaid readhead portion of a magnetic head.

FIG. 2 is a side cross-sectional view of another prior art lead overlaidread head portion of a magnetic head.

FIG. 3 is a side cross-sectional view of a first preferred embodiment ofa lead overlaid read head portion of a magnetic head of the presentinvention.

FIG. 4 is a perspective drawing of a magnetic disk drive system inaccordance with one embodiment.

FIGS. 5A-D graphically illustrate the fabrication of a sensor havinganti-parallel tab regions using a Chemical Mechanical Polishing (CMP)lift-off process.

FIG. 6 is a detailed illustration of the structure of FIG. 5C taken fromCircle 6 of FIG. 5C.

FIG. 7 is a detailed illustration of the structure of FIG. 5D taken fromCircle 7 of FIG. 5D.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description is the best embodiment presently contemplatedfor carrying out the present invention. This description is made for thepurpose of illustrating the general principles of the present inventionand is not meant to limit the inventive concepts claimed herein.

Referring now to FIG. 4, there is shown a disk drive 400 embodying thepresent invention. As shown in FIG. 4, at least one rotatable magneticdisk 412 is supported on a spindle 414 and rotated by a disk drive motor418. The magnetic recording media on each disk is in the form of anannular pattern of concentric data tracks (not shown) on disk 412.

At least one slider 413 is positioned adjacent to the disk 412, eachslider 413 supporting one or more magnetic read/write heads 421. Moreinformation regarding such heads 421 will be set forth hereinafterduring reference to FIGS. 5-7. As the disks rotate, slider 413 is movedradially in and out over disk surface 422 so that heads 421 may accessdifferent tracks of the disk where desired data are recorded. Eachslider 413 is attached to an actuator arm 419 by way of a suspension415. The suspension 415 provides a slight spring force which biasesslider 413 against the disk surface 422. Each actuator arm 419 isattached to an actuator means 427. The actuator means 427 as shown inFIG. 4 may be a voice coil motor (VCM). The VCM comprises a coil movablewithin a fixed magnetic field, the direction and speed of the coilmovements being controlled by the motor current signals supplied bycontroller 429.

During operation of the disk storage system, the rotation of disk 412generates an air bearing between slider 413 and disk surface 422 whichexerts an upward force or lift on the slider. The air bearing thuscounter-balances the slight spring force of suspension 415 and supportsslider 413 off and slightly above the disk surface by a small,substantially constant spacing during normal operation.

The various components of the disk storage system are controlled inoperation by control signals generated by control unit 429, such asaccess control signals and internal clock signals. Typically, controlunit 429 comprises logic control circuits, storage means and amicroprocessor. The control unit 429 generates control signals tocontrol various system operations such as drive motor control signals online 423 and head position and seek control signals on line 428. Thecontrol signals on line 428 provide the desired current profiles tooptimally move and position slider 413 to the desired data track on disk412. Read and write signals are communicated to and from read/writeheads 421 by way of recording channel 425.

The above description of a typical magnetic disk storage system, and theaccompanying illustration of FIG. 4 are for representation purposesonly. It should be apparent that disk storage systems may contain alarge number of disks and actuators, and each actuator may support anumber of sliders.

FIGS. 5A-D graphically illustrate the fabrication of a sensor havinganti-parallel tab regions using a Chemical Mechanical Polishing (CMP)lift-off process. In this method, the active area of the sensor isprotected and untouched during the fabrication. This assures improvedperformance/sensor stability over the alternative methods describedabove where the bias layer in the active area is oxidized to kill itsmagnetization or physically removed.

FIG. 5A illustrates a partially formed wafer upon which read headsensors 500 are formed. As shown, the starting substrate is a free layer504 formed on a suitable substrate 502 and capped with Ta and/or Ru cap506. Ta works well to protect the sensor, and is compatible with mostprocesses. Note also that the substrate 502 can be formed using anysuitable process and in any suitable structure, including thosediscussed above with reference to FIGS. 1-4.

In an illustrative embodiment, the substrate can include a substratebase that constitutes the material from which the slider is fabricated,such as aluminum titanium carbide. A first magnetic shield is fabricatedon the substrate, and an insulation layer, typically composed ofaluminum oxide, is fabricated upon the magnetic shield. A seed layer isdeposited upon the insulation layer and a series of thin film layers aresequentially deposited upon the seed layer to form a GMR read head. Inthis structure, the layers generally include an antiferromagnetic layer,a pinned magnetic layer that is deposited upon the anti ferromagneticlayer, a spacer layer that is deposited upon the pinned magnetic layer,and the free magnetic layer 504 deposited upon the spacer layer. Theantiferromagnetic layer may be composed of PtMn; the pinned magneticlayer may be composed of CoFe, NiFe, or some combination therof; thespacer layer may be composed of Cu; the free magnetic layer may becomposed of CoFe, NiFe, or some combination therof; and the cap layermay be composed of Ta. Note that other materials may also be used.

The process steps are outlined for bottom GMR here i.e., pinned layer atbottom. Layers of Diamond Like Carbon (DLC) 510 and resist 512 are addedto the structure. The DLC/Resist layers 510, 512 are coated andpatterned (i.e., by photolithography and deposition) as in a standardCMP process. Then, using photolithography and etching, material isselectively removed from the area herein referred to as tab areas. Theactive sensor area stays covered with DLC. The area still covered byDLC/resist forms the active area 544 of the sensor. Tab areas 560 aredefined on opposite sides of the active areas 544.

FIG. 5B illustrates processing of the tab areas 560 of the structureshown in FIG. 5A. As shown, the Ta/Ru cap 506 is removed from the tabarea, preferably using Reactive Ion Etching (RIE). RIE only removes thecap and does not affect the sensor. Then the tab area is ion milled(sputter cleaned) to remove residual Ta/Ru from the sensor. The DLC 510protects the active areas 544 from damage during these processes. Notethat a portion of the sensor in the tab area has also been removedduring the milling. This is acceptable, because the milled portion ofthe sensor (in the tab areas) will be inactive once the bias layer isformed thereon. Thus, it is permissible to mill into the free layer 504and refill with fresh soft magnetic material if necessary. In thisexample, up to about 15 Angstroms of material can be removed from thetab area of the free layer 504 without adverse consequences.

FIG. 5C illustrates addition of spacer, bias, cap, and lead layers tothe structure shown in FIG. 5B. As shown in FIG. 5C, the tab areas 560of the free layer 504 are refilled with the same material as theexisting free layer 504 to bring the thickness of the free layer 504 inthe tab areas 560 to about the same thickness as in the active areas544. This additional refilled material 504 will also become part ofstack 520.

With continued reference to FIG. 5C, the spacer, bias, cap, and leadlayers are shown collectively as layer 520. The spacer layer is formedover the free layer 504. Ru in a layer of about 5-10 Å is the preferredmaterial for the spacer layer, though Cr can also be used, preferably ina thickness about less than about 10 Å, ideally about 8-10 Å. The spacerlayer is operable to make magnetic moments of ferromagnetic layers onopposite sides thereof antiparallel. A bias layer is then deposited. Thebias layer is operative to substantially pin magnetic moments of the tabareas of the free layer. The bias layer is preferably composed of FeN,and ideally mostly Fe with a small amount of N, e.g., 2-5%. Materialssuch as NiFe can also be used. A cap layer is formed on the bias layer.The cap layer can be of Ta. Then leads are deposited above the biaslayers. Illustrative materials for the leads include Au and Rh.

Magnetically, the free and bias layers may require a certain thicknessto be effective. In one example where NiFe is used for the bias layer,the bias layer is about 25% thicker (as measured vertically in thestructure shown in the drawings) than the free layer 504. For example,if the free layer 504 is about 30 Å, the bias layer is about 37 to 40 Å.FeN has about twice the magnetic moment of NiFe. Because FeN has twicethe moment, an FeN bias layer need only be half as thick as a layer ofNiFe. Thus, in the foregoing example, the FeN bias layer would only needto be about 15-20 Å thick. A preferred thickness of the bias layer is50-80% less than the thickness of the free layer 504. A DLC overcoat 528is added to the structure of FIG. 5C.

FIG. 6 is a detailed illustration of the structure of FIG. 5C taken fromCircle 6 of FIG. 5C. As shown, the spacer layer is denoted by referencenumeral 522, the bias layer is denoted by reference numeral 524, the caplayer is denoted by reference numeral 526, and the lead layer is denotedby reference numeral 530.

FIG. 5D shows the removal of the several layers from the structure ofFIG. 5C. A CMP lift-off process is used to remove any materials above aplane 532 extending parallel to portions of the second layer of DLC 528in the tab regions. The DLC is not affected by the CMP, and isdeliberately left in place to protect the layers under it. Then RIE isused to remove the remaining DLC 510, 528. RIE will not damage theunderlying layers.

After the above processes have been completed, each sensor active area544 has the following structure: free layer/Ta/Ru. The tab areas 560each have the following structure: free layer/Ru/bias layer (e.g.CoFe/NiFe)/cap/lead. The magnetic moments of the tab areas of the freelayer are pinned antiparallel to moments of the bias layers. The biaslayer will typically have a thickness profile that is thicker near themiddle of the tab area than at the edges (near the active area of thesensor). It is more important to have proper thicknesses at the edge ofthe track because that is where it is critical to pin the underlyingportion of the free layer. Also, the spacer layer is not continuousacross the sensor, as the spacer layer remains only in the tab area.Note too that the bias layers may show signs of oxidation.

FIG. 7 is a detailed illustration of the structure of FIG. 5D taken fromCircle 7 of FIG. 5D.

One major advantage of this method is that the active area free layermaterial is untouched by subsequent manufacturing processes. Since thetab area of the free layer is pinned, small increase in Hc/Hk by theprocesses will not degrade performance. The active area of the headwhere the sensor is sensing flux from the disk is very sensitive toflux, i.e., is very soft. So it is desirable that Hc/Hk be very small.During prior art processing, the oxidation of the bias layer in theactive region could contaminate the free layer, leading to an increasein Hc/Hk, which would degrade performance. The processes describedherein do not touch the active area, but rather affect the tab areas.Because the free layer is pinned in the tab areas, some degradation ofthe free layer in the tab areas will not affect performance.

This method of fabrication is also applicable to other structures,including CPP GMR and Tunnel Valve sensors. This process also allows useof oxidation to raise the resistivity of the AP-Tab region for TV andCPP GMR application to avoid current spreading problem. The bias layercan be oxidized to raise its resistance before the cap and leaddeposition.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. For example, the structures and methodologies presentedherein are generic in their application to all MR heads, AMR heads, GMRheads, spin valve heads, etc. Thus, the breadth and scope of a preferredembodiment should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

1. A method for fabricating a sensor having anti-parallel tab regions,comprising: forming a free layer having tab areas on opposite sides ofan active area; forming a first layer of a carbon composition above theactive area of the free layer; forming a bias layer above the tab areasof the free layer, the bias layer being operative to substantially pinmagnetic moments of the tab areas of the free layer wherein prior toforming the bias layers, forming spacer layers above the tab areas ofthe free layer, the spacer layers being operable to make magneticmoments of the tab areas of the free layer and of the bias layersantiparallel; forming a second layer of carbon composition above the tabareas of the free layer; removing the layers of carbon composition andany portions of the layers overlying the layers of carbon composition.2. A method as recited in claim 1, wherein the first layer of carboncomposition is formed by patterning and coating.
 3. A method as recitedin claim 1, further comprising forming a cap layer on the free layerprior to forming the first layer of carbon composition, and removing thecap layer from the tab areas of the free layer prior to forming the biaslayers.
 4. A method as recited in claim 3, wherein a portion of the freelayer is also removed during removal of the cap layer.
 5. A method asrecited in claim 1, wherein the spacer layers comprise at least one ofRu and Cr.
 6. A method as recited in claim 1, further comprising forminga cap on the bias layer.
 7. A method as recited in claim 1, furthercomprising forming a lead above the bias layer in the tab area.
 8. Amethod as recited in claim 1, wherein the magnetic moments of the tabareas of the free layer are antiparallel to moments of portions of thepinned layer above the tab areas of the free layer.
 9. A method asrecited in claim 1, further comprising at least partially oxidizing thebias layer.
 10. A method as recited in claim 9, wherein the removing thelayers of carbon composition and any portions of the layers overlyingthe layers of carbon composition includes chemical mechanical polishingand reactive ion etching processes.
 11. A method as recited in claim 1,wherein the sensor forms part of a GMR head.
 12. A method as recited inclaim 1, wherein the sensor is a CPP GMR sensor.
 13. A method as recitedin claim 1, wherein the sensor is a tunnel valve sensor.
 14. A methodfor fabricating a sensor having anti-parallel tab regions, comprising:forming a free layer having tab areas on opposite sides of an activearea; forming a first layer of a carbon composition above the activearea of the free layer, the first layer of carbon being substantiallyabsent from tab areas of the free area; forming a layer of resist abovethe first layer of carbon composition; removing the resist from abovethe tab areas; forming spacer layers above the tab areas of the freelayer, the spacer layers being operable to make magnetic moments offerromagnetic layers on opposite sides thereof antiparallel; formingbias layers above the spacer layers, the bias layers being operative tosubstantially pin magnetic moments of the tab areas of the free layer;forming second layers of carbon composition above the tab areas of thefree layer; removing the layers of carbon composition and any portionsof the layers overlying the layers of carbon composition.
 15. A methodas recited in claim 14, wherein the spacer layers comprise at least oneof Ru and Cr.
 16. A method as recited in claim 14, wherein the magneticmoments of the tab areas of the free layer are pinned antiparallel tomoments of portions of the bias layer above the tab areas of the freelayer.
 17. A method as recited in claim 14, further comprising at leastpartially oxidizing the bias layer.